Language Processors

These are the software used to translate different High Level and Assembly Language Programs into Machine Language.
There are three types of Language processor:

• Compiler
• Interpreter
• Assembler

Compiler:
Computer hardware can only understand the machine language or hardware language. It is necessary to convert the instructions of a program written in high level language to machine instructions before the program can be executed by the computer. A compiler carries out this job. Thus a compiler is a translating program that translates the instructions of high level language into machine language. A compiler can translate only those source programs, which have been written in the language for which the compiler is meant. For example a FORTRAN compiler is only capable of translating source programs, which have been written in FORTRAN, and therefore each machine requires a separate compiler for each high level language.

Interpreter:
An interpreter is another type of translator used for translating high level languages into machine code. It takes one statement of a high level language and translates it into a machine instruction, which is immediately executed. Translation and execution alternate for each statement encountered in the high level language program. In other words an interpreter translates one instruction and the control unit executes the resulting machine code, the next instruction is translated and the control unit executes the machine code instruction and so on. This differs from a compiler, which merely translates the entire source program into an object program and is not involved in its execution

Assembler:
This is a type of a translator. It also works in the same way as compiler and interpreter works. It is a program, which translates an assembly language program to its machine language equivalent.